-- little helper function
function file_exists(path)
  local attr = lighty.stat(path)
  if (attr) then
      return true
  else
      return false
  end
end
function removePrefix(str, prefix)
  return str:sub(1,#prefix+1) == prefix.."/" and str:sub(#prefix+2)
end

-- prefix without the trailing slash
local prefix = '/drupal'

-- the magic ;)
if (not file_exists(lighty.env["physical.path"])) then
    -- file still missing. pass it to the fastcgi backend
    request_uri = removePrefix(lighty.env["uri.path"], prefix)
    if request_uri then
      lighty.env["uri.path"]          = prefix .. "/index.php"
      local uriquery = lighty.env["uri.query"] or ""
      lighty.env["uri.query"] = uriquery .. (uriquery ~= "" and "&" or "") .. "q=" .. request_uri
      lighty.env["physical.rel-path"] = lighty.env["uri.path"]
      lighty.env["request.orig-uri"]  = lighty.env["request.uri"]
      lighty.env["physical.path"]     = lighty.env["physical.doc-root"] .. lighty.env["physical.rel-path"]
    end
end
-- fallthrough will put it back into the lighty request loop
-- that means we get the 304 handling for free. ;)